The present invention relates to a termite shielding structure of underfloor portions of a building for preventing termites from entering the underfloor portions from underground.
In case ventilation of underfloor portions of a building is poor, it is often the case that the building is eroded by termites. Termites, with the exception of some minor kinds thereof, favorably breed on temperate and humid soil and exist by absorbing moisture from nature. By entering underfloor portions from cracks in foundations or peripheries of underground piping from soil in the periphery of the building, the termites erode wooden materials constituting the building or even furniture.
Principal measures that have conventionally been taken to prevent termites from entering or to get rid of them are chemical measures employing chemicals such as insecticides or termite shielding chemicals. More particularly, such measures include directly dispersing insecticides at places where termites inhabit, killing the termites either directly or indirectly by inducing the termites to baits, or utilizing wooden materials that preliminarily underwent termite shielding treatments by using chemicals. There are also taken measures for keeping termites away from wooden material portions of a building by forming a barrier through dispersing termite shielding chemicals into soil in the periphery of the building or laying a termite shielding sheet on a ground surface corresponding to underfloor portions of the building. Floor slab concrete may be poured above the surface of the soil on which the termite shielding chemicals have been dispersed or above the termite shielding sheet that has been laid on the soil surface for suppressing purposes.
However, while such chemical measures that are dependent on chemical efficacy of termite shielding chemicals or insecticides are capable of performing termite shielding treatments or getting rid of them in a relatively short time when and where required, it cannot be avoided that the toxicity of the chemicals badly affect the peripheral environment as well as other creatures. That is, it may be that a person performing chemical treatments may breathe in chemicals or that chemicals that have been dispersed into the soil and to underfloor portions are spread to harm the health of residents. Wooden materials that have undergone termite shielding treatments through chemicals are limited in their purposes when being reused, and they may pollute the environment when being disposed. Further, since the chemical efficacy of chemicals vanish after a short term, it will be necessary to repeatedly perform chemical treatments within effective periods so that such a measure is not an economical one in terms of trouble and costs in a long-term aspect.